u/GWINhvac

I live in Minnesota and am converting my detached garage into a workshop. Approximately 575 sqft, 9 foot ceilings, R13 in walls, R49 in ceiling, insulated garage door with green hinges and draft sealing. Basically, about as insulated and sealed as a garage can get without building from scratch.

I don't really care about cooling capacity, but I'd like to keep the garage in the 50-60F range for most of the winter. This includes weeks of single digit temps. I've estimated I need about 24k but of heating for this, but I'm thinking I may pay for a CoolCalc to get a more confident Manual J calculation to verify.

I've been researching mini splits and have determined that the Blue Ridge XS5 24k BTU appears to have the best cold weather performance and HSPF2 Region V rating among the "direct to consumer" mini splits. Their XS6 18k BTU has great cold weather performance and efficiency as well, but I'm worried it won't have the oomph for deep winter and they don't have a 24k BTU option.

I don't need a DIY option, I'm comfortable renting the equipment to vac the line sets. I have received multiple quotes for this between $8-12k which to me is absolutely obscene. They try to really sell me on the warranty but I can replace a unit 2-3 times over for that price. I'm open to any brand or model that sells directly to consumer and has good support. Alpine Home Air has blown me away with their support so far.

We live in Mammoth Lakes, CA and have been finding it difficult to find an HVAC company to quote a minisplit system for us. I think we're ready to throw in the towel and go the DIY route.

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We got one quote for $29k for a 36k btu Mitsubishi hyper heat with 4 indoor units, not including any electrical work or permit. This seems very high.

Another company came over to look at our space and recommended Samsung, but now they've ghosted us.

A third wants at least $300 just to have a look, which fair enough, but haven't pulled the trigger on them yet.

There are a few more options that I'll contact, but being in a small rural area, prepared to not find a pro.

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Our specs:

- Downstairs is 550 sq ft, L shaped, 8' ceilings.
- Three upstairs bedrooms, all about 150 sq ft.
- We live at 8,000' elevation.
- According to the town, our winter design temp is -2F (summer 74F).
- I did an online manual J for our downstairs area (can't remember the site now, but it has been recommended on this sub) and got 15-16.5k btu heating. I do not think this accounted for our elevation, though.

Our setup:

- We primarily use the wood stove downstairs for heating, but want a heat pump to maintain 65-68ish overnight or when we don't light the fire.
- Also have baseboard and wall heaters; these would be removed in rooms where indoor unit added.
- Interested in AC for when we close our windows for wildfire smoke.
- No possibility for ducting. Upstairs we have lofted ceilings with giant beams and no attic.

Our challenges:

- One of the bedrooms would require the indoor unit to both be mounted on an inside wall, and have the lineset run through walls/floors to later become mostly inaccessible (without ripping into finished surfaces). Samsung guy said no to this, Mitsubishi said it would work. We are fine either way, thoughts?
- Our elevation makes sizing a challenge I think?

Other questions:

- I was thinking either 15k or 18k for downstairs, and 6k for each room. Does that sound right?
- Mr Cool for the DIY aspect, so we can have a warranty?
- Any other thoughts or considerations?

Appreciate any guidance you can give me, thank you!

Our central ac and heat unit sounds like it is on its last legs.

Wife wants to replace the current attic unit and outside condenser with a mini split system??

Our single family home is about 1000 square feet, two bedrooms.

I said I don't want a head unit/cassette/wall mounted unit in every room because they are large, our rooms are small and the whole thing would be unsightly.

She said " What you do is put in an "air handler" in the attic and connect that to the current duct work. So no wall head units would be needed inside.

So everything on the inside of the house would look the same, thermostat, vents etc.

And this new system would be more efficient and save us money.

Is this a thing? Anybody know about this or done it?

For background : house with attic, about 1000 sqft, southern California. House built in the 50s

Hey everyone! I'm u/GWINhvac, a founding moderator of r/diyminisplit. This is our home for all things related to diy ductless mini splits. We're excited to have you join us!

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GWIN Assisted DIY, makes it easy for a company of many trades to install a professional system. They do all the install which a lot of hvac companies sub-out anyways… and we send a tech to pressure test for leaks, then vac and charge the system! Best part is, we are one of the few companies that give a full warranty on DIY installs. In fact, we give even more warranty on a DIY install!

The Evolution of DIY Mini Splits

GWIN™ Assisted DIY™

Most DIY mini splits still leave the hardest parts up to you — pressure testing, vacuuming the system, handling refrigerant, or finding your own tech, and even dealing with bulky pre-charged line sets. GWIN™ HVAC changes all of that with Assisted DIY™.GWIN™ having the Assisted DIY™ is an evolution over DIY alone and makes GWIN™ a complete DIY mini split system that includes free expert tech support, with a tech included, so you never need special tools, never touch refrigerant, never run a vacuum pump, and never perform a pressure test. Our line sets with our easy connect flare-less fittings, allow for a professional operating system, with a professional look. Which also means no coiled mess and no guesswork — just a straightforward self-install ductless system that goes in like a true DIY HVAC project, backed by professionals every step of the way. Whether you're cooling or heating a garage, basement, bedroom, sunroom, home addition, tiny home, or cabin — GWIN™ HVAC is the ultimate DIY ductless solution with our Assisted DIY™ for homeowners who want to do it themselves, but done right." GWIN™ HVAC is the advanced version of DIY mini splits. 

What is Assisted DIY™ and why is it better than DIY alone?

The other DIY brands did a good thing making hvac available to the homeowner, and more affordably at that. Where they fell short was leaving them hanging when things get shipped not working, or after the install when issues arise. The big deal is when you buy DIY, you get DIY… You’re not getting a tech at all, even if there is an issue with the equipment from the factory, it’s your problem. If you have a problem, most techs don’t want to service the equipment, and that can be an issue.
So how does GWIN™** **handle this any differently? For starters GWIN™ is the first and only company to offer Assisted DIY™ which has a Tech Included™ with every system. This is equally as good as buying a pre-charged lineset, but better. This solves so many problems, and makes things so much easier for the homeowner. They never have to worry about getting a tech, because one is included from the beginning free of charge. The homeowner handles all of the install, just like all the other DIY systems. One major overlooked advantage is that the lineset can easily be cut to length, and connected using our easy connect flare-less fittings. Our lineset assembly allows the system to look and work professionally just as it was intended. 
Once the install is complete, the homeowner simply calls GWIN directly, and we schedule the tech, communicating directly between the two. The great thing is, no matter where you are in the 48 contagious US states, you are guaranteed a tech, or you get your system free. I mean… that quite a guarantee. Once the tech is scheduled, he comes, pressure test your system for leaks, then will vac and charge your system. The great thing is, Its all included. That’s definitely an evolution over pre-charged linesets and DIY in general.

GWIN really backs the homeowner, especially with a DIY installation with our Bumper to Bumper one year warranty. For one whole year after the tech commissions the system, the customer install labor is fully covered, the tech labor is fully covered, and refrigerant is fully covered. So if a tech missed a leak during the pressure test, we pay to have it fixed, and we pay for the refrigerant as well. The warranty gets better… lets say if a system gets unknowingly damaged and installed, such as a control board not working, or some crazy issue that’s not a installer issue, its fully covered when the tech comes, and we pay to have them fix it. 

GWIN doesn’t even stop there… some really big problems were solved. The equipment comes with a 10yr parts and compressor warranty that stays with the equipment, no matter who owns it or installs it. Plus we partnered with one of the largest hvac part suppliers in the US to supply parts for our 10yr warranty. So you never have to worry about getting parts. For 10yrs if parts are ever needed, they are shipped directly to your door from the closet supply house to your location. 

This is what Assisted DIY™ is… and we do our best to make sure that you are always Assisted.

GWIN assisted diy makes it easy… the included tech gives the assurance. So proud of our team to be able to walk our first time customers through being able to make such a professional looking install! Blows me away!

New customer starting a GWIN install